The present invention relates in general to coating technology. More particularly, it relates to a method for forming a material capable of forming a self-cleaning surface on an object.
The wettability of solid surfaces is a very important property, and is governed by both the chemical composition and geometrical microstructure of the surface. Currently, hydrophobic surfaces with water contact angle higher than 130° are arousing much interest because they will bring great convenience in daily life as well as in many industrial processes. Various phenomena, such as snow sticking, contamination or oxidation, are expected to be inhibited on such a surface.
An important application for these hydrophobic surfaces is the production of self-cleaning coatings based on their water and dirt repellency. These self-cleaning coatings not only provide value-added products with a high potential to save on cleaning and other maintenance cost, but also are good for ecobalance of the coated product, since cleaning chemicals no longer pollute the water and since energy is saved by reducing or eliminating maintenance cycles.
Conventionally, hydrophobic surfaces have been produced mainly in two ways. One is to create a rough structure on a hydrophobic surface, and the other is to modify a rough surface by materials with low surface free energy. Unfortunately, both approaches have several issues to deal with. Most hydrophobic coatings with surface roughness do not exhibit sufficient mechanical strength and adhesion, which results in short lifetimes. Others modified with low surface energy materials generally do not exhibit sufficient hydrophobicity (contact angle with water>130°) or adhesion.
Accordingly, the invention is generally directed to formation of a durable self-cleaning coating with improved mechanical strength and adhesion while maintaining a high water contact angle for the self-cleaning effect to work.